Time of Flight

Q. A football is kicked with a velocity of 20 m/s at an angle of ${45}^{\circ }$ with the horizontal. Find the time taken by the ball (in sec) to strike the ground. Give answer correct to 1 decimal place
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Q. In case of projectile motion if two projectiles A and B are projected with same speed at angles ${15}^{\circ }$ and ${75}^{\circ }$ respectively to the horizontal then:

1. $H_A=H_B$
2. $H_A<H_B$
3. $T_A=T_B$
4. $T_A<T_B$

Q. Referring to above question, the angle with the horizontal at which the projectile was projected is

1. $ta{n}^{-1}\left(\frac{3}{4}\right)$
2. $ta{n}^{-1}\left(\frac{4}{3}\right)$
3. $si{n}^{-1}\left(\frac{3}{4}\right)$
4. $Notobtainablefromthegivendata$

Q. A projectile can have the same range R for two angles of projection. If $t_{1}and{t}_2$ are the times of flight in the
two cases, then

1. 
2. 
3. 
4. 

Q. A football player throws a ball with a velocity of 50 metre/sec at an angle 30 degrees from the horizontal. The ball remains in the air for $(g=10m/s^2)$

1. 2.5 sec
2. 1.25 sec
3. 5 sec
4. 0.625 sec

Q. A $0.098\text{kg}$ block slides down a frictionless track as shown (Assume no energy loss on the entire track)
The time taken by the block to move from A to B is

1. $\frac{1}{\sqrt{g}}$
2. $\frac{2}{\sqrt{g}}$
3. $\frac{3}{\sqrt{g}}$
4. $\frac{4}{\sqrt{g}}$

Q. On seeing enemy ships at a distance of 125 m from the shore, the canons start firing fireballs. The captain of the ship saw the cannon fire. He knows the velocity of the fireballs is 50 m/s. Now in how much time does he have to steer his ship in some other direction so as to save his crew. Use angle of projection as ${30}^{\circ }$. Also find the maximum height that the fireball reaches above water.

1. T = 5s, H = 31.25 m

2. T = 5s, H = 45.6 m

3. T = 11s, H = 31.25 m

4. T = 10s, H = 45.1 m